Research On Hybrid LDPC Decoding Algorithm Based On Bit-Flipping

The mobile communication has developed rapidly within a few decades and it is becoming an indispensable part of human life. Although technology in all areas reached to a high level in performance, we still have to improve and strengthen the current technology in order to meet the growing needs of human beings. We generally reduce costs by improving the performance of current technology and reduce complexity of the algorithm which is beneficial to put technology into piratical use.Low-density parity-check(LDPC) code has been widely used because of its high error correction performance, simple description and low decoding complexity. One of the important research on current LDPC code is to improve the decoding algorithm. Overall, we can improve the algorithm in two ways: enhance the decoding performance or reduce the complexity of decoding algorithm. At present decoding algorithm based on bit-flipping, the cycle in Tanner graph is the major limitation to the decoding performance. Thus, how to break the cycle becomes the determining factor to improve performance. So in recent years, researchers have proposed a variety loop detection algorithm and made varying degrees of improvement in bit-flipping algorithm.This dissertation proposed a new idea on cycle-jumping based the different transfer path in different decoding algorithm. It proposed two hybrid decoding algorithm based bit-flipping. The first one is Cyclic switching mixed weighted bit-flipping(CS-MWBF) decoding algorithm, this algorithm uses the continuous transformation decoder for two weighted bit-flipping decoding algorithms after cycle-testing to jump up the cycles. So that the original decoding error bits can be decoded correctly. The simulation shows that compared with LC-WBF and IM-WBF decoding algorithms, CS-MWBF algorithm achieves more about 0.1-0.4dB coding performance with almost the same computational complexity. The second one is Hybrid-switching two-bit weighted bit-flipping(HS-TWBF)decoding algorithm, this algorithm uses the two-bit bit-flipping and transformation of two decoding algorithms based on cycle-testing to jump up the cycles. HS-TWBF algorithm achieves about 0.3-0.8dB coding gain over LC-WBF, IM-WBF and RR-WBF algorithms, and the iterative decoding speed is doubled. The two kinds of new algorithms have improvement in decoding performance and decoding speed, with obvious advantages in computational and space complexity compared with other cycle-testing or cycle-jumping algorithms. So the two new algorithms have wide application significance.